If $x \star y = 2x-4y$ and $x \circledcirc y = 4x-7$, find $(3 \star 0) \circledcirc -2$.
First, find $3 \star 0$ $ 3 \star 0 = (2)(3)-(4)(0)$ $ \hphantom{3 \star 0} = 6$ Now, find $6 \circledcirc -2$ $ 6 \circledcirc -2 = (4)(6)-7$ $ \hphantom{6 \circledcirc -2} = 17$.